Today drilling rigs are used for bolting in mining. Said rigs comprise a bolting device, which can be used for drilling holes in mine drifts as well as for bolting. Bolting in mine drifts is advantageous in a number of ways.
According to a known construction, said bolting device comprises a drilling unit and a bolting unit, which are arranged to be supported by a bottom carriage via a respective top carriage. Said bottom carriage is adapted to be supported by a feed beam, relative to which said bottom carriage is displaceable, wherein said top carriages are arranged to be alternately supported by said bottom carriage in order to alternately be brought into operative engagement and hereby alternately be locked relative to said bottom carriage.
The bottom carriage is hereby equipped with a hinged plate, which at a specific position, which allows switching of said top carriages, rotates around a suspension element. Said plate is in operation brought into engagement in a groove of the top carriage that is currently arranged for operation at the bolting device. The rotation of the plate is caused by a fully mechanical mechanism.
A disadvantage of this technique is that the plate is exposed to an undesirable wear, wherein the reliability in operation may be adversely affected. Said wear is difficult or impossible to inspect without disassembling the bolting device for visual inspection.
There is thus a need to achieve a reliable bolting device, in which the locking mechanism of said carriages is easy to inspect continuously.
U.S. Pat. No. 4,351,625 discloses a device for automatic bolting in rock reinforcement operations. The device has a drilling unit, an injector device, a bolting machine and a feed arm. The device also includes a switching mechanism for switching between various functionalities of the device.
SE465094 describes a mechanical locking pin, which by means of a hinged arm is moved to a locked and an unlocked position. The locking pin is moved to the locked position by a spring and comprises a hole in the top carriage when the bottom and top carriage are moved along the feed beam.